..Thus a balance between endogenous pSmad3 and active Notch controls the regenerative competence of muscle stem cells, and deregulation of this balance in the old muscle microniche interferes with regeneration...

..Comprehensively, this work points toward novel venues for in situ restoration of tissue repair in the old and identifies critical determinants of successful cell-replacement therapies for aged degenerating organs...

hESC-secreted proteins can be enriched for multiple regenerative therapies by heparin-binding

..Moreover, hESC-secreted factors improve the viability of human cortical neurons in an Alzheimer's disease (AD) model, suggesting that these factors can enhance the maintenance and regeneration of multiple tissues in the aging body. ..

Heterochronic parabiosis for the study of the effects of aging on stem cells and their niches

..Here we review current literature on the relationship between the vigor of tissue stem cells and the process of aging, with an emphasis on the rejuvenation of old tissues by the extrinsic modifications of stem cell niches...

Richard I SherwoodDepartment of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USACell 119:543-54. 2004

..Together, these studies describe the clonal isolation of functional adult myogenic progenitors and demonstrate that these cells do not arise from hematopoietic or other bone marrow or circulating precursors...